Use of a non-woven fabric having a surface covered with microfiber for the preparation of cleaning devices

ABSTRACT

There is described the use as textile material to produce cleaning devices of a “double-layer” non-woven fabric having a microfiber layer supported by a macrofiber layer wherein the layers are bonded by needle-punching and subsequent treatment of the microfiber surface with high pressure water jets.

The present invention relates to the use of a non-woven fabric having a surface covered with microfiber for producing cleaning devices, such as mops, conventional floor cloths, cloths for glass and for any other type of surface.

In particular, the present invention relates to the use in the cleaning sector of “double layer” composite textile materials formed by a microfiber surface layer and a non-woven fabric supporting layer.

In the cleaning sector non-woven fabric materials completely in microfiber are particularly appreciated, as they are very effective in the removal of dirt, due to the fineness of the fibers of which they are composed, normally less than 1 dtex. To obtain a thickness that is sufficient to allow easy handling for use as cleaning cloths, or to produce strip mops, the weight per square meter of the material must be greatly increased, thus increasing costs due to the quantity of fibers used. Moreover, increasing the weight of the product in this way leads to high production costs, as to obtain cohesion of the fibers inside the layer of non-woven fabric high pressure water jets are required during the hydroentanglement process generally used to form non-woven fabrics of microfiber.

The use of microfiber has also recently be introduced in the manufacture of cloths formed by flexible strips defined as mops but more commonly known with the trade name “mocio®”. In these mops a small surface portion of the outermost strips is made of microfiber, while the remaining part is made of fibers having deniers greater than 1 dtex (macrofibers). These materials are produced by thermally bonding a microfiber layer with a macrofiber layer, and subsequently by optionally calendering the double layer thus obtained, in which each layer has been prepared previously according to respective prior art techniques. However, this thermal process is costly from the viewpoint of energy and due to the use of hot melt glues which are required to allow adhesion of the two different layers. Moreover, bonding of the two different layers by hot rolling also causes a decrease in the cleaning efficacy of the microfiber as the heat bonds the filaments of the microfiber together, decreasing their number and consequently the cleaning capacity of the microfiber layer.

The object of the present invention is to find a textile material to be used in the cleaning sector capable of overcoming the aforesaid drawbacks of prior art and with a high cleaning power comparable to microfiber, high mechanical consistency and integrity even at low densities, with lower costs with respect to microfiber so that it can be used to produce any type of cleaning device.

A further object is that of finding a material of this type that has improved cleaning and abrasive power, also in the case of microfiber with low weight per square meter.

Yet another object of the present invention is that of using a material of this type that is practical and inexpensive.

The present invention relates to the use, in the preparation of cleaning devices, of a non-woven fabric textile material with at least two layers (hereinafter also defined as “double layer”, one of which is made of microfiber, wherein said microfiber layer is supported by non-woven fabric layer in macrofiber, and wherein longitudinal lines alternated with embossments or micro-embossments are preferably present on the microfiber layer.

“Cleaning devices” are intended herein as mops, sponges, conventional floor cloths, cloths for glass, and for any other type of surface, etc.

The term “microfiber” is intended as defining very fine fibers, generally synthetic, having a count equal to or less than 1 dtex (UNI 10714-1999), i.e. ten thousand meters of a fiber weigh one gram, while the term “macrofiber” is intended herein as fibers with a count greater than 1 dtex.

The aforesaid double-layer textile material is obtained by carrying out a first step of needle punching a mat formed by at least one layer of carded web of macrofibers and at least one layer of carded web of microfibers, and a subsequent treating the needle-punched mat with spunlace/hydroentangled technology with high pressure water jets to open the microfibers into filaments, where the needle-punching and subsequent treatment are performed and applied from the same side in microfiber, i.e. on the free surface of the microfiber layer of the mat.

The macrofiber layer to be used in the needle-punching step can be pre-needled, needle-punched or even only constituted by a plurality of crosslapped or carded webs. The effect of the use of the macrofiber layer is achieved provided that a microfiber web layer is deposited over said macrofiber layer and that subsequent needle-punching is performed only on this microfiber side.

Both the mechanical needle-punching step and the hydroentanglement step are performed according to prior art. In particular, for hydroentanglement see for example U.S. Pat. No. 3,485,706, or the description of patent application EP 1359241 incorporated herein by reference.

In practice, the first mechanical needle-punching step produces a non-woven fabric, which is used as base for application to one of its two surfaces of a splittable microfiber web; then, always with the prior art mechanical needle-punching technique, this surface web of fibers is entangled by taking, through mechanical action, the fibrils of the microfiber inside the lower layer of non-woven macrofibers so as to cover one of the two surfaces with microfiber and to bond the two different layers of non-woven fabric though entanglement of the fibrils of the surface layer with those of the layer below. In this manner, the fibril is given its direction by the needle that conveys it inside the lower supporting layer, without contaminating the microfiber layer with less prestigious macrofibers, which instead would occur in the case of bonding only using mechanical needle-punching, as in the art needle-punching is also performed on the lower side of the mat.

Subsequent to this operation, surface bonding is applied using the prior art technique of hydroentanglement, again only on one side on which the microfibers have been deposited so as to entangle the fibres of the surface and, in case of microfibers, also to split the fibrils so as to produce microfibers as a result of hydroentanglement.

The high pressure hydroentangling step is carried out by means of a device with water jets that apply a pressure generally in the order of 80/400 bar on the free surface of the upper microfiber layer of the mat, along the lines of the nozzles which are distributed in various ways (mutually adjacent and in contact with one another, or suitable spaced apart so as to create different paths). Said lines represent bonding lines along which the microfibers are bonded to a greater degree with the macrofibers below. In this bonding operation final entanglement of the microfibers occurs, with formation of the cleaning layer fixed to the supporting layer at said longitudinal bonding lines, preferably spaced apart from one another so that they are alternated. Along said lines the fibres are more compressed due to the previous water jet and therefore, in the case of longitudinal lines spaced apart, the microfiber surface has embossments or micro-embossments alternated with said lines.

Subsequently, the bonded product is air dried and wound on a reel or can be coated with resins, preferably acrylic resins, on the macrofiber side (i.e. on the free surface of the macrofiber layer) to obtain fabrics with one side similar to chamois leather, which are very effective for cleaning glass.

The non-woven fabric thus produced can be used as is, or can be subsequently dyed and/or coated on both sides and/or printed on one or other side, to produce dry and/or moistened cloths for cleaning, to produce mops or for use in the medical sector, where fabrics with different densities and compositions are required, and in all those applications that require the efficacy of microfiber which, due to the physical structure of the fibers of which it is composed, removes dirt very effectively.

Macrofibers can be used as fibers for the lower supporting layer, with the same or different deniers, made of viscose, polypropylene, nylon, rayon, cellulose, mixed viscose and polyester, cotton and the like. Alternatively, it is possible to use fibers deriving from regenerated or recycled materials, for example 100% recycled PET, or from a mixture of 70% regenerated cellulose fibres and 30% recycled PET fibres.

A preferred composition of macrofibers contains 70% of viscose and 30% of polyester, or a 50/50 mixture of viscose/polyester.

The unit weight (basis weight) of the macrofiber layer can vary between 50 g/m² and 300 g/m², preferably greater than 100 g/m², for example comprised between 180 and 280 g/m², more preferably comprised between 200 and 250 g/m². It is understood that macrofibers with greater unit weight could also be used, such as 400 g/m², without departing from the spirit of the present invention.

The fibers of the microfiber layer are preferably splittable fibers formed, for example, by polyester/polyamide, and having deniers of around 1-2 Dtex before being split which are capable of generating microfilaments (multi filaments) having deniers below 1 Dtex. This microfiber can have a unit weight similar to that of the macrofiber layer or lower, preferably lower, for example comprised between 40-70 g/m².

A preferred embodiment of the textile material used in the present invention provides an upper microfiber layer with unit weight comprised between 60-70 g/m² and a lower non-woven fabric macrofiber layer with unit weight comprised between 200 and 250 g/m².

The total thickness of the textile material and/or of its single layers is not binding for the purposes of the present invention and depends on the final use of the material. For example to produce mops, a non-woven fabric with total thickness varying between 1 mm and 3 mm and with a thickness of the microfiber layer comprised between 0.3 mm and 1 mm can be used.

The use of the material of the present invention is particularly advantageous as a smaller quantity of microfiber is used with respect to known bonded materials obtained by hot rolling, without however sacrificing the mechanical consistency of the material which is guaranteed by the macrofiber layer. In particular, as only the filaments on the surface of the microfiber layer “work” against the dirt, in the material used in the present invention it is also possible to use a microfiber having a low unit weight, for example 20 g/m², while guaranteeing mechanical strength and consistency of the material due to the macrofiber supporting layer which can be used with a high unit weight, for example greater than 100 g/m², as it is less prestigious than the microfiber.

Moreover, any presence of embossments on the microfiber surface provides an improved cleaning power with respect to conventional microfiber materials as said surface is even rougher and more abrasive, with a “spatula” effect that allows more effective removal of dirt and grease with respect to conventional microfiber cloths.

Numerous modifications and variations of detail within the range of those skilled in the art could be made to the present embodiment of the invention, all however falling within the scope of the invention expressed by the appended claims. 

1. Method of producing from a textile material cleaning devices and/or medical textiles of a “double layer” non-woven fabric comprising a microfiber cleaning layer and a macrofiber supporting layer, said fabric being obtained by carrying out a first step of needle-punching of a mat formed by at least one layer of carded web of macrofibers and at least one layer of carded web of microfibers, and a subsequent step of treating the needle-punched mat with high pressure water jets, said needle-punching and treatment being performed from the same side on the free surface of the microfiber layer .
 2. The method according to claim 1, wherein the unit weight of the microfiber is equal to or less than 100 g/m², preferably 70 g/m², more preferably 40-70 g/m².
 3. The method according to claim 1, wherein the surface of the microfiber layer comprises longitudinal bonding lines alternated with embossments or micro-embossments.
 4. The method according to claim 1, wherein the free surface of the macrofiber layer is coated with resins, preferably acrylic resins.
 5. The method according to claim 1, wherein the fibers of the macrofiber layer are made of viscose, polypropylene, nylon, rayon, cellulose, mixed viscose and polyester, cotton and the like, preferably formed by 70% of viscose and 30% of polyester, or by a 50/50 mixture of viscose/polyester; or they are formed by regenerated or recycled materials, for example 100% recycled PET, a mixture of 70% regenerated cellulose fibres and 30% recycled PET fibres.
 6. The method according to claim 1, wherein the microfibers are splittable fibres constituted by polyester/polyamide.
 7. The method according to claim 1, wherein the basis weight of macrofiber layer ranges from 100 g/m² to 400 g/m², preferably comprised between 180 and 280 g/m², more preferably comprised between 200 and 250 g/m².
 8. Material in double-layer non-woven fabric as defined in claim 1 having one of surfaces thereof covered with a microfiber layer.
 9. Cleaning devices and/or medical textiles comprising at least one textile material as defined in claim 8, preferably in form of mops, conventional floor cloths, cloths for glass and for any other type of surface, sponges, dry and/or moistened cloths for cleaning, or cloths for use in the medical sector where fabrics with different densities and compositions are required, an in all those applications in which the efficacy of microfiber is required. 